The present disclosure relates generally to the field of actuators in a building automation system. The present disclosure relates more particularly to an actuator capable of accepting a power supply line voltage input in a heating, ventilation, and air conditioning (HVAC) system for a building.
A building automation system (BAS) is, in general, a system of devices configured to control, monitor, and manage equipment in or around a building or building area. A BAS can include a HVAC system, a security system, a lighting system, a fire alerting system, another system that is capable of managing building functions or devices, or any combination thereof. BAS devices may be installed in any environment (e.g., an indoor area or an outdoor area) and the environment may include any number of buildings, spaces, zones, rooms, or areas. A BAS may include METASYS building controllers or other devices sold by Johnson Controls, Inc., as well as building devices and components from other sources.
A BAS may include one or more computer systems (e.g., servers, BAS controllers, etc.) that serve as enterprise level controllers, application or data servers, head nodes, master controllers, or field controllers for the BAS. Such computer systems may communicate with multiple downstream building systems or subsystems (e.g., an HVAC system, a security system, etc.) according to like or disparate protocols (e.g., LON, BACnet, etc.). The computer systems may also provide one or more human-machine interfaces or client interfaces (e.g., graphical user interfaces, reporting interfaces, text-based computer interfaces, client-facing web services, web servers that provide pages to web clients, etc.) for controlling, viewing, or otherwise interacting with the BAS, its subsystems, and devices. A BAS may include various types of controllable equipment (e.g., chillers, boilers, air handling units, dampers, motors, actuators, pumps, fans, etc.) that can be used to achieve a desired environment, state, or condition within a controlled space.
Some HVAC actuators require an input voltage of approximately 24 VAC for proper operation. However, a typical BAS in which the actuators are implemented provides electric power at a standard power supply line voltage (e.g., 120 VAC or 230 VAC at 50/60 Hz). Previous systems generally require the use of transformers or switching power supplies to provide the actuators with the required input voltage. It can be complicated and expensive to implement such devices in many HVAC systems. It would be desirable for an actuator in a HVAC system to accept a voltage input at a power supply line voltage.